First the scripts provided here are very limited and could be dangerous due to missing argument checking. Second they even don't work here on by Mac as I have a FHS conforming 10.3.9 where bash is at /usr/bin/ and NOT /bin as provided by Apple. You should NEVER assume that a given tool or folder is where Apple installed it! And btw your del cemmand could be archived with a simple alias del='mv...'

There is also a much better rmm 'command' available (for free) with support for nearly ever rm option including recursion.